AP Chemistry Homework - Percentage by weight?

My AP [Advance Placement] Chemistry teacher threw this problem at me for homework... and I am so lost on where to start. Please help! TT~TT 1) A 2.000 gram sample containing graphite (carbon) and an inert substance was burned in oxygen and produced a mixture of carbon dioxide and carbon monoxide in the mole... show more My AP [Advance Placement] Chemistry teacher threw this problem at me for homework... and I am so lost on where to start. Please help! TT~TT

1) A 2.000 gram sample containing graphite (carbon) and an inert substance was burned in oxygen and produced a mixture of carbon dioxide and carbon monoxide in the mole ration 2.00 : 1.00. The volume of oxygen used was 747.0 milliliters at 1,092K and 12.00 atmospheres pressure. Calculate the percentage by weight of the graphite in the original mixture.

I'm going to take a guess and say the formula for this is...
PV = nRT ?

Thanks for your time. =]
1 answer 1